1. Field of the Invention
The present invention relates to a chip removal method and a chip removal system, and in particular, to a chip removal method and a chip removal system for machine tools of a numerically controlled type.
2. Description of the Related Art
The machine tool is configured for machining a work, generally with a machining mechanism including a combination of a tool and a worktable for the machining, a machine frame for operatively supporting the machining mechanism, a plurality of drives for driving the machining mechanism, and a controller for quantitatively controlling the drives.
A typical machine tool adapted for a milling is equipped with a chip remover for automatically removing chips out of a machining region, without delay, as they are produced as a work is milled. The chip remover is configured with a removing mechanism for removing chips, a support frame for supporting the removing mechanism, a drive for driving the removing mechanism, and a switching element for turning the drive on and off. While running, the chip remover has faint vibrations transmitted from the drive and the removing mechanism to the support frame. The chip remover""s support frame is fixed to the machine tool""s machine frame, so that vibrations are transmitted from the former to the latter, as well, which however is not so serious as to give bad influences on a normal machining of the machine tool.
Machine tools in which the quantitative drive control is digitized are called xe2x80x9cnumerically controlled machine toolxe2x80x9d (hereinafter referred to xe2x80x9cNC machine toolxe2x80x9d), which has a numerically controlling controller (hereinafter called xe2x80x9cNC controllerxe2x80x9d). The NC controller is configured with a numerically controlling program (hereinafter called xe2x80x9cNC programxe2x80x9d) adapted for calculating necessary amounts of control for drives to drive components of machining mechanism to be displaced, as necessary, and giving commands indicating the necessary control amounts, and a computer adapted to output the commands to the drives.
For the machine tool, the precision of machining is important. The machining precision of a machine tool is restricted by various errors. These are caused by internal factors such as operational conditions of and physical properties in the machine tool, and external factors such as environmental conditions about the machine tool.
For any error, whether the factor is internal or external, if a program to compensate for the influence is provided, the NC controller faithfully executes the same to calculate necessary control amount. Accordingly, the NC machine tool, allowed to have a high precision, is applicable to a work to be machined with a free surface, such as a mold.
In a process of finishing a free surface of work to a high precision with an NC machine tool provided with a chip remover, the inventors have found that vibrations accompanying removal of chips have their influences transferred on a finished surface, as a problem. Compensation for such influences of vibration might have been effected by numerical control, however with an increased complexity of NC program, as the precision of machining is increased. The present invention has been made to intrinsically avoid the problem.
It therefore is an object of the invention to provide a chip removal method and a chip removal system for NC machine tools, in which vibrations accompanying removal of chips have no influences transferred on a finished surface of work.
To achieve the object, according to an aspect of the invention, a chip removal method for NC machine tools comprises defining a portion of a chip remover vibratory to give an NC machine tool a vibration transferable onto a surface of a work under a finishing by the NC machine tool, making a decision whether the NC machine tool enters the finishing, and controlling vibration of the vibratory portion, as the decision is true.
To achieve the object, according to another aspect of the invention, a chip removal system for NC machine tools comprises a chip remover having a portion defined to be vibratory to give an NC machine tool a vibration transferable onto a surface of a work under a finishing by the NC machine tool, a decision maker making a decision whether the NC machine tool enters the finishing, and a controller controlling vibration of the vibratory portion, as the decision is true.
According to the aspects above, in the finishing of the work, the vibration transferable onto the surface of the work under the finishing is controlled, so that the problem of vibration transfer is intrinsically avoidable, without causing an associated NC program to have increased complexity, even with an increased precision for the finishing.